TREATMENT OF BANCROFTIAN FILARIASIS IN RECIFE, BRAZIL - A 2-YEAR COMPARATIVE-STUDY OF THE EFFICACY OF SINGLE TREATMENTS WITH IVERMECTIN OR DIETHYLCARBAMAZINE

The effectiveness of single oral doses of ivermectin (200 or 400 mu g/ kg) and diethylcarbamazine (DEC, 6 mg/kg), preceded 4 d earlier by eit her placebo or very small doses of these drugs, was compared, over a 2 -year period, in a double-blind trial in 67 microfilaraemic Brazilian men with bancroftian filariasis. Regimens containing ivermectin alone decreased the number of microfilariae significantly faster and more ef fectively for the first month after treatment than regimens containing DEC alone, but the latter were significantly more effective throughou t the second year after treatment (1.7-8.2% of pretreatment levels wit h DEC vs. 12.6-30.8% with ivermectin during that period); the higher i vermectin dose showed a tendency towards more effectiveness than the l ower dose. Most effective was the combination of ivermectin (20 mu g/k g) followed 4 d later by DEC (6 mg/kg), with reduction of microfilarae mia to 2.4% of pretreatment levels at 2 years. Adverse reactions were well tolerated with all regimens, the reactions being significantly mo re generalized (i.e., fever) following ivermectin and localized (i.e., scrotal inflammatory nodules around dying adult worms) following DEC. Further trials of single-dose combination therapy vs. single high dos es of ivermectin or DEC should determine the ideal regimen for treatme nt and control of bancroftian filariasis.